A249876 Pseudo-lucky numbers.

1, 3, 5, 7, 11, 13, 17, 21, 23, 25, 31, 35, 41, 43, 45, 47, 55, 57, 63, 65, 73, 75, 83, 87, 95, 97, 101, 105, 107, 113, 123, 127, 131, 133, 141, 143, 147, 151, 153, 161, 175, 177, 183, 185, 197, 201, 211, 213, 215, 217, 227, 233, 235, 237, 251, 255, 265, 267

Offset

1,2

Comments

Appears to grow more slowly than the Lucky numbers. - Jon Perry, Nov 07 2014

Links

Jean-François Alcover, Table of n, a(n) for n = 1..1000

Example

Start with the natural numbers. The 2nd number is 2, so delete every 2nd number, leaving 1 3 5 7 9 11 13 15 17 19...; the 3rd number remaining is 5, so delete every 5th number, leaving 1 3 5 7 11 13 15 17 ...; now delete every 7th number, leaving 1 3 5 7 11 13 17 ...; now delete every 11th number; etc.

Maple

L:= [seq(i, i=1..10^3)]:
for n from 2 while n < nops(L) do
  r:= L[n];
  L:= subsop(seq(r*i=NULL, i=1..nops(L)/r), L);
od:
L;

Mathematica

FixedPoint[Function[{L}, n++; Delete[L, List /@ (L[[n]]*Range[Quotient[Length[L], L[[n]] ]])]], n=1; Range[1000]] (* Jean-François Alcover, Nov 27 2014 *)

Prog

(Python)
def listed(n):
   L=list(range(1, n+1)); j=1
   while L[j] <= len(L):
      L=[L[i] for i in range(len(L)) if (i+1)%L[j]!=0]
      j+=1
   return(L)

Crossrefs

Cf. A000959 (Lucky numbers).

Sequence in context: A062280 A069467 A309739 * A096169 A225526 A090670

Adjacent sequences: A249873 A249874 A249875 * A249877 A249878 A249879

Keyword

nonn

Author

Robert FERREOL, Nov 07 2014

Status

approved